Electric fuse



Patented June 16, 1925.

UNITED STATES HENRY T. BUSSMANN, OF ST. LOUIS, MISSOURI.

ELECTRIC FUSE.

' Application filed May 7,

To all whom-it may concern:

Be it known that I, HENRY T. BUSSMANN, a citizen of the United States, residing at St. Louis, Misouri, have invented a certain new and useful Electric Fuse, of which the following is a full, clear, and exact descri tion, such as will enable others skilled in the art to make and use the same.

My invent-ion relates to electric fuses and refers particularly to that type of fuse known as the refillable cartridge knife blade type; yet I do not limit my invention to this type-as certain of my improvements are likewise desirable in other types of fuses.

It is well known that fiber, which is principally used as a casing, will shrink and swell, making it difiicult to provide removable closures for the casing, that are satisfactory. For this reason, I provide a mem-. ber attached to each end of the casing, referably of metal or other material 0 unchanging dimensions, for the holding of the closures. V

This member also serves to eliminate the difliculties experienced by the ed ewise movement of the terminals caused y inserting the fuse into the jaws of a fuse block. This edgewise movement results in injury to the fuse link or loosening of its fastenings, resulting in poor contact, and consequent premature burn-out of the fuse-link.

Another object of my invention is to ro-- vide a means for assuring the assemb age of the terminals and fuse link in a straight are. The difficulty has been that when the bolt intended for this urpose is pulled up tight, it invariably-pulls the terminals out of line with the link, making it impossible to assemble the fuse. a

These and other advantages of m invention will be more readily under by ref erence to the accompanying drawings, which show a referred form of my invention. In descri ing the device shown in the drawings hereto attached and described in the "specifications, I do not limit my invention to the precise form, shape or construction of the fuse shown, or to the several parts thereof, as various alterations can be made withoutrhanging the scope of my invention.

Fig. 1 is a view'of my fuse havin a sec- -ztion broken out to show the interior arrangement thereof. Fig- 2 is a like view showing the interior of the fuse ninety de grees removed from that shownin Fig. 1. Fig. 3 is an end view of the fuse. Fig. 4

side walls. Through the slot 10 of the closure 8 there 1919. Serial N0. 295,869.

shows a. terminal and part of a fuse strip with means for securing and aligning the terminal and strip. Fig. 5 shows a modified form of my improved fuse.

In the drawings, 5 is a casing, 6 is a member extending partially within the casing. As shown in the drawings, this member is in the shape of a ring having a shoulder thereon. It is obvious that various changes may, however, be made inthe shape of this member, and while I prefer to use a member fitted inside the casing, et, I may use one fitted outside, although the latter is unsatisfactory because the fiber shrinks away from it. 7 is a portion of the outer periphery, which is threaded to engage and hold the casing. 8 is a closure. 9 are screws which attach the closure 8 to the member 6. This closure may be in the form of a cap having extends the terminal 11. On the interior of the member 6, I provide bearing points hav ing a spaced relation to each other, between which points the terminal is positioned with only a limited clearance. When the terminal is subjected to edgewise movement, as, for instance, when a fuse is inserted in a fuse block, the terminal will bear on the points 16, 16, or 17, 17, and by reason of the separation of these points and the small .clearance allowed the terminal, only a very limited movement of the terminal is The terminal 11 and fuse strip 12 are connected by means of a bolt 13, which passes through the holes in the terminal and fuse strip. 14 is a projection preferably stamped out of the terminal, as shown in Fig. 2, and 15 is a recess in the fuse strip to engage with the projection 14. When so positioned the terminal and fuse strip are rigidly held in predetermined alignment and .r-?cannot be ulled out of such alignment when fastening the bolts.

To hold the terminal against longitudinal I and removably fitted, with a certain limited movement, I provide a terminal holding device, preferably a bar, as shown at 18, which is located on the outside of the closure, al-

though I may place this bar under theclosure, in which case I would prefer to recess the member to position the bar. This bar is held by the closure holding screws 9 and fits into slot 19 in the terminal. I prefer to make this slot of a length greater than the thickness of the bar. By this means I am able to adjust any variation in .the length ofthe fusible element comprising terminal and fuse link, or variations in length of the casing, occasioned by the shrinkage of the fiber. It is obvious that I may make this slot of only such a length as to just fit the bar, if other means are provided to prevent or adjust the variations mentioned.

Any suitable form of fuse link may be used in my fuse. I

I claim as my invention:

1. In an enclosed fuse, a casing, a member permanently attached to the casing, a flatblade terminal adapted to be passed through said casing, a closure and means extending through the end face of the member detachably securing the closure.

2. In a refillable fuse, a tubular casing, a member having a threaded portion for securement "to the casing, a terminal adapted to be removably positioned within the. easing, a closure fitted about the terminal, and means on the end face of the member for detachably securing the closure to the end of said member.

3. In a refillable fuse, a casing, a ringshaped member having i-tsinner periphery of constant dimension, a flat-blade terminal adapted to bepassed through the member clearance within the member and held for against edgewise movement relative to the member.

4. In a refillable fuse, a casing, a ringshaped member, a flat-blade terminal adapted to pass therethrough, said member having oppositely disposed means in constant spaced relation to each other between which the terminal at its edges is removably positioned with a certain limited clearance, whereby edgewise movement of the terminal is substantially prevented.

5. In an enclosed fuse, a casing, a member attached to the casing permanently, a terminal extending within said member, said terminal having an aperture outside of said member, a terminal holding device secured to said member and engaging said aperture to limit the longitudinal movement of said member.

6. In a fuse, a casing, a closure, a terminal and a device outside the closure adapted to hold the terminal against inward and outward movement.

7. In a fuse, a casing, a terminal having an aperture therein, a terminal holding device engaging said aperture, said engaging portion 0 the device having such a lesser width than the length of the aperture as to permit a certain limited longitudinal movement of the terminal relative to the terminal holding device.

8. In a refillable fuse, a structure comprising a casing and closures therefor, a pair of terminals and a fuselink connected to form a fusible element, there being an aperture in the terminal and terminal holding device engaging said aperture and permitting a certain limited longitudinal movement of the terminal relative to the terminal-holding device.

HENRY T. BUSSMANN. 

